Starting switch



C. F. GILCHRIST. SARTING SWITCH. F1 LED Nov. 30, 1917.

.Mm m. wm.

Patented dan., 23, 1923.

UNlTED STATES CLARENCE r. cfrLcHRrs'r, or Torneo, omo.

STARTING SWITCH.

Application iled November [o all whom t may concern.:

Be it known that ll, CLARENCE F. Gru.- oHIus'r, a citizen of the United States, residing at Toledo, in the county of Lucas and State offUhio, have invented certain new and usefullmprovements in Starting Switches, of which ll declare the following to be a full, clear, and exact description.

rlhis invention relates to electric switches,

1u particularly of that class employed in the electrical circuit of a starting motorl for internal combustion engines. y

'll he object of this invention is to provide a switch of the above named class, which will have a very low resistance to the passage of electricity, and at the saine time be of compact form. A further object is to devise a switch with an intermediary contact which will automatically adjust itself to the 2u various parts. Another object is to provide a switch of the type above indicated, which will vary its resistance in proportion to the degree of compression of the actuating means.

Further objects, and objects relating to economies of manufacture and details of construction, will definitely appear from the detailed description to follow:

l accomplish the objects of my invention 3o by the devices described in the following specification. My invention is clearly defined and pointed out in the appended claims.

A structure constituting a preferred embodiment of my invention is illustrated in` the accompanying drawings, forming a part of this specification, in which:

Figure ll is a View, in side elevation, of the switch connected in circuit with la starting motor and a battery;

Figure lll is a vertical section taken ou line ll-lll of Figure HI;

Figure lllll is a horizontal section, taken on line lllll-lllll of Figure Ill;4

Figure lll, and,

Figure V is a section taken on line V-V of Figure lll.

lin the drawings, similar reference numerals refer to similar parts throughout the several views, and the sectional views are taken looking in the direction of the little arrows at the ends of the section lines.

As illustrated, the switch comprises in brief, a supporting plate 1, an operating 30, 1917. Serial N0.2l)l1,62.

button 2, a connecting rod 3, a contact ring il, terminal contacts 5 and 6, and casing 7. rllhe supporting plate l has apertures 8 to receive bolts or screws for attaching the switch to the vehicle. Centrally disposed in the plate is a raised cylindrical bearing 9, apertured aslat 1(), to receive the actuating rod 3. The diameter of the aperture 1() is increased at ll, to receive an absorbent packing 12, designed to receive oil to lubricatc the actuating shaft and to keep out dust from the switch interior. The shaft 3 is a cylindrical metal rod, slidable in the bearing 9 and has attached at its upper terminal` by means of a pin 13, an operating button 2, and towards its lower end, the contact ring 4. The button consists of a metal unit having a bead 14, a body 15, and a hollow cap 16, designed to fit over the support bearing 9 and serving as a guide to the downward movement of the connecting rod 2l.

The base 17, of the cap 16, Serves as an abutment to limit the downward movement of the rod.

Towards the lower end of the connecting rod 3, the contact ring 4 is applied.` This ringis made of a circular band of copper, and fits loosely over an insulating bushing 18. An insulating washer 19, holds the ring from axial movement on the bushing and the whole is held together and in place on the rod by `means of metallic washers 2Ul and 21. Bearing on the lower washer 21, at the base of the ring bushing 18, and encircling the rod 3, is the upper terminal ofy a spiral bandmspring 22. 'lhe lower end of this springft'erminates adjacent the end of the rod 3, and rhas a bearing on the hase 23, of the cylindrical casing l7, which is attached to the supportingzplate,1,1byscrews24. The contact terminals-5 and G are identical in construction, andy consist of resilient bands of metal,bent into semi-circular form, from Onesideyof which extend converging strip -dinger "2 mwithi` out-turned terminals 26. yThese ontacts are placed inside the casing with `the semi-circular bands 27, in juxtapositionfbut not in contact, thus forming, in effect, a hollowed inverted truncated cone with resilient sides. These separated contacts 5 and li'are fastened at diametrically opposite points to the casing 7, at points where they are normally out of `engagement with the ring 1, but such that, on downward movement, the ring will Contact firmly therefingers tends to keep them clean and smooth, l

with. The contacts are secured in place by means of bolts 28, which with the contacts are insulated from the casing 7 by a circular insulating ring 29. The bolts are further insulated from the casing by the insulator rings 30 and 31.

ers 32, and nuts 33, the nuts in addition binding the circuit terminals 34 in place. In the casing base 23, the operating rod 3 is movable through an aperture 35, which centers the rod and serves as a bearing therefor. n

The operation of the switch will now be described. When the button 2 is depressed against the resistance of the spiral spring 22, the ring 4 moves downwardly, until it contacts with the resilient fingers, thereby completing the electrical circuit. If the rod 3 is ofi center, relative to the spring fingers 25 and 26, the ring, since it is movable laterally, is shifted until it bears with equal pressure on the opposing spring contact fingers. Further compression of the ring 4 forces the fingers outwardly, the changmg curvature of the same allowingof greater contact area between the contacting parts, until the limit of movement is reached where the compression of the fingers and area of contact is greatest, and therefore the resistance is least.l It is evident that the sliding action of the ring on the contact and thus increase the electrical conductance at the points of contact.

I am aware that the particular embodiment of my invention, here. shownv and described, is susceptible of considerable variation without departing from the spirit ofmy invention, and, therefore, I desire to claim the same broadly, as well as specifically., as indicated by the appended claims.

aving thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

*1. In an electric switch, the combination of a casing; a supporting plate; a connecting rod movable transversely through vthe supporting plate; an. actuating button on one end of the connecting rod; a contact ring adjacent the other end of the connecting rod and insulated therefrom, said ring being capable of lateral movement only, relative-to the connection rod; terminal inwardly. pro.- jecting contact fingers attached to the casing and insulated therefrom; and a spiral spring intermediate the contact ring and casin adapted normally to hold the ring and ngersout of contact with each other.

2. In an electric switch, the combination The bolts and insulators. are held firmly in place by the metallic washof a longitudinally reciprocable actuating rod; a pair of contacts normally insulated from each other and each provided with a plurality of curved contact fingers; and a ring mounted on said rod and insulated therefrom, said ring being adapted to engage said fingers to electrically connect said contacts together, and said ring having a slight lateral movement relative to said rod. In an electric switch, the combination of a longitudinally 'reciprocable actuating rod; a pair of contacts normally insulated from each other and each provided with a curved contact fin er; and a ring mounted onsaid rod and msulated therefrom, said ring beine adapted to engage said fingers to electrically connect the said contacts together, and said ring being constructed to have a limited lateral movement relative to said rod whereby it ma engage the two contacts with substantial y equal pressure.

4. In an electric push button'switch., a cylindrical casing, a pair of curved contact members secured to said casing each having aplurality of inwardly extending fingers, a pushrod extending through said casing, a contact ring having a cylindrical outer surface mounted on said push rod to have limited lateral movement thereon, the fingers initially contacting with an edge of the ring and finally contacting with the said cylindrical surface whereby the said ring is self adjusting toV bear with substantiall ual pressure on both sets of fingers and t e nal contact resistance is less than the initial contact resistance.

5. In an' electric push button switch, a cylindrical, casing, a pair of curved resilient contact members within said casing, a terminal post electrically connected to and securing each of said members to the curved .wall of said lcasing, said posts extending radially from opposite sides'of said casing, a push rod extending through said casing, and a contact member carried by said rod to have sliding engagement with said. contact 

